


Testing a Theory

by SupernaturallyObsessed



Category: Grimm (TV)
Genre: Anal Fingering, Anal Sex, Dirty Talk, M/M, Mentions of Sex Toys, Plot What Plot/Porn Without Plot, Smut, Spanking, did I mention smut?
Language: English
Status: Completed
Published: 2018-09-02
Updated: 2018-09-02
Packaged: 2019-07-05 17:15:23
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,309
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/15868119
Author URL: https://archiveofourown.org/users/SupernaturallyObsessed/pseuds/SupernaturallyObsessed
Summary: Sean Renard was lost in his thoughts about what he had just seen. Nicholas Burkhardt, the sexiest man in the Portland police department, had been staring at him and blushing. He’d had feelings for the young detective for a long time but he'd always assumed the other man was completely straight and not at all interested in him.Maybe those thoughts had been wrong.Sean smirked. He might have to test that later.





	Testing a Theory

**Author's Note:**

> I've written smut before but this is the dirtiest thing I've ever written. Ya'll are a bad influence. ;)

 

 

They’d been dancing around each other for a while. Years really. Nicholas Burkhardt had thought Sean Renard was attractive from the moment he’d met the man.

The police captain was six feet four inches of muscle and power. Commanding to a level so few people were. Nick had gotten used to his own height and hated when people thought they could dominate or overpower him simply because they’d been blessed with taller genes. There was something about Renard though that made Nick crave to get down on his knees and submit. 

Usually Nick liked to be in charge--he wanted to be the one doing the fucking not the one getting fucked--but he would go ass up for Renard in a heartbeat.

“Earth to Nick Burkhardt!” Hank called, lightly tossing a pen at his partner.

Nick jumped, pulled out of his daydream. “What?” 

“Man, where were you?” Hank asked, chuckling a little. “You zoned out and have been staring at the Captain’s office for nearly five minutes.” 

“I have?” Nick really hoped he wasn't blushing as much as he felt like he might be. By the way Hank was smirking at him though he figured the chances weren't good. To make matters worse, Captain Renard chose that exact moment to look up from where he was working at his desk and make eye contact with the young detective. The older man raised an eyebrow and smirked a little before turning his attention back to his laptop.

Nick groaned and dropped his head to his desk. Ogling his superior was bad enough. Getting caught doing it by both his partner and said superior was more embarrassment than he wanted to deal with.

*

Sean Renard looked at his laptop but didn't focus on what was on the screen. He was lost in his thoughts about what he had just seen. Nicholas Burkhardt, the sexiest man in the Portland police department, had been staring at him and blushing. 

He’d had feelings for the young detective for a long time but, due to the fact that he was Nick’s captain and their complicated history as Grimm and half-zauberbiest, he’d never made a move. He'd also always assumed the other man was completely straight and not at all interested in him. 

Maybe those thoughts had been wrong.

Sean smirked. He might have to test that later.

 

=+=+=+=+=+=+=+=+=+=+=

 

The opportunity for Sean to test his theory came two days later. It was after ten o’clock at night so practically everyone had gone home. Sean was still in his office taking care of business in Portland as well as talking to a couple of contacts in other countries. It was common for him to stay late at the office some days, but he was surprised to see Detective Burkhardt still at his desk. 

Sean closed his laptop and and stood up. He walked over to the doorway of his office and leaned casually against the frame. “What are you still doing here, Burkhardt?” he asked. He kept his voice serious but made sure he didn't actually sound angry. He definitely wasn't angry because, if he played his cards right, he would be very, very satisfied by the time the night was over.

Nick jumped in his chair when he heard the captain call his name. “Oh...sorry, Sir,” he stuttered. “Just catching up on some paperwork. Guess I lost track of time.”

Sean hummed. “Come into my office for a minute,” he said. He didn't let his tone give anything away, but he tried to convey his intention in his eyes. Without waiting to see if Nick would follow him, Sean stepped back in his office and began lowering the blinds.

“What can I do for you, Captain?” Nick asked when he joined the older man in his office. 

“You can start by locking the door,” Sean replied suggestively.

“Uh...okay.” Nick closed and locked the office door. He was trying very hard to not let his imagination run away with him. There were plenty of possible reasons why his incredibly attractive captain would call him into his office late at night with the blinds closed and the door locked. Plenty of logical explanations that didn't include the sexual fantasies Nick’s brain was thinking up. “So what did you want to talk about?” Nick asked, working hard to control his racing heart rate. 

Sean moved to lean against the front of his desk. “Here's the thing, I have something I'd like to do tonight--actually, I have a lot of things I'd like to do tonight--but due to our work dynamic I can't be the one to ask for it.” The man smirked and loosened his tie, hoping he was getting his message across without being forceful. “So, is there anything _you_ would like to talk about?”

Nick tried to swallow despite the dryness in his mouth. Was the man really asking what Nick thought he was? “Are you asking me to…”

“I'm not asking you to do anything,” Sean said, cutting him off. He made eye contact with Nick because this was serious. He was fairly confident he was right in his suspicions but he had to be sure. Had to let Nick make the first move. “I'm just giving you an opportunity to speak if there’s anything you want to do or say. If you don't have anything in mind then you're completely free to leave and we won't talk about this again.”

“And if there is something I want?” Nick asked after a moment, stepping closer to Sean. He had found his footing in the conversation and felt comfortable with the situation but he wanted to make sure he was right before saying too much.

Sean took a deep breath to steady himself. He had to stay in control, at least for a little longer. “Then all you have to do is ask and, if I am willing and able, I will give it to you.” 

Nick tried to think of a delicate way to ask about what he had in mind but then decided that he needed a clear answer and to get that he would have to ask a direct question. He wanted to test the waters one more time first though and slowly licked his lips. Nick saw Sean follow the action with his eyes and it was all the confirmation the younger man needed. He took another step closer so that he was standing right in front of Sean and had to tilt his head up to see eye to eye with the man. “Will you fuck me?” 

Running out of patience, Sean didn't waste time answering with words. Instead he quickly took hold of the detective’s face and leaned down to ravage his mouth. “Yes,” he rasped out when they separated for some air.

Concerns addressed, both men moved past their hesitations and quickly began stripping each other. They each kicked off their shoes and Nick pushed Sean’s suit jacket down his arms and ripped off his tie while Sean focused on pulling off Nick’s sweater and undershirt. Sean moved his hands to undo the buttons on his shirt but Nick pushed them away and started to take care of it himself. With his hands free, Sean tilted Nick’s head up and pulled him into a heated kiss. When Sean’s tongue probed at Nick’s lips the younger man instantly opened up and let the royal take everything he wanted.

Sean hated having to pull away but he needed to in order to catch his breath and get out of his shirt. Once he was free, however, the older man pulled Nick into another kiss. He’d wanted to do this for a long time and now that he could he was going to enjoy it. After a minute Sean broke the kiss and dropped his hands from Nick’s face in favor of taking hold of the younger man’s hand to pull him around to the other side of the desk. He opened the bottom drawer and dug around for a moment before pulling out a bottle of lubricant.

“You seriously keep lube in your office?” Nick asked, incredulous. Truthfully he was thankful for the discovery--it had been awhile since he’d last done this and while he liked it rough he didn't want to be really hurt--but it was definitely a surprise.

“This isn't some heat of the moment desire, Nick,” Sean explained. He leaned forward so he was nuzzling Nick’s cheek and speaking right into the detective’s ear. “I've wanted you for years and have fantasized about all the different ways I would take you. I figured I should be prepared just in case.”

Nick chuckled with an impish glint in his eyes. He pulled back so that he could meet his superior’s gaze. “Well then, how do you want me, _Sir_?”

Sean groaned. Hearing Nick call him sir in this context was on his list of fantasies. Mentally running through said list, the man tried to decide how to answer Nick’s question. 

There were so many possibilities: Nick kneeling on Sean’s office chair while the older man fucked him from behind; Sean in his chair watching as Nick fucked himself on his cock; Nick on his knees with Sean’s cock in his mouth; the list went on. There was one idea that stood out in that moment, however.

“Bend over the desk,” Sean said, voice laced with steel as he tried to keep himself controlled.

“You fantasize about this while filling out paperwork?” Nick teased, not yet moving from his spot.

“Mmm,” Sean said thoughtfully. “Do you?” he asked, smirking down at his detective. He wasn’t about to let Nick have the upper hand in this game. “Have you ever been in here updating me on a case and thought about me bending you over this desk, pulling down your pants, and filling you up with my big cock?” 

Now it was Nick’s turn to moan. “Yes,” he managed to gasp out. It was true; he had thought about being fucked by the captain before. Many times in fact. “Almost...almost all the time,” he whispered.

“What was that?” Sean asked. The smirk on his face made it clear that he had heard exactly what Nick said but that he wanted to make the man repeat the statement just to rile him up more.

“I've thought about being fucked by you,” Nick said. “I always thought about it occasionally but once Juliette and I broke up I no longer had to feel guilty fantasizing about you.” Nick was surprised that he was admitting to so much but the words were just tumbling out of his mouth. He slid a hand down Sean’s smooth and muscled chest. “I bet you're proportional everywhere.” His hand rested lightly over where Sean's cock was straining against his pants. “Would make me feel you for days.”

Sean chuckled darkly. “Oh you won't walk straight for a week once I'm through with you.”

Nick looked up at the older man and smirked. “Prove it.”

Sean growled and turned Nick around before shoving the younger man down so his chest rested on the desk in front of them. He kept one hand on Nick’s back to hold him down while the other hand reached around to open his jeans and push them down his legs along with his boxers.

Looking at the detective’s perfect ass, Sean caved to temptation and brought his hand down on the firm globe with a solid _smack_. Not hard enough to cause real pain but enough to leave a warm sting. Sean froze instantly, fearing that he had just ruined everything due to his sudden action. Usually it was polite to ask before spanking someone. He didn't even know if Nick liked it rough. To his surprise, however, the younger man actually moaned in what sounded like pleasure.

“Did you enjoy that, Nicholas?” Sean asked tentatively. Maybe things weren't as bad as he'd feared.

Nick closed his eyes tightly and bit his lip, not wanting to admit just how much he had enjoyed it. He hadn't known before that spanking would be such a turn on for him, but the feeling of his captain’s large hand smacking down on the tender skin of his ass had been delightfully intense, and he wanted more.

Sean chuckled. He'd become fairly adept at reading Nick over the years and he had a feeling he knew exactly what his detective was thinking. “Do you want more, Nick?” Sean asked, voice rough with desire. “Do you want me to spank you? Make your ass bright red with my handprints?” Nick moaned again. “All you have to do is say yes, Nick. Say it and I'll give you what you want.”

Nick tried to resist but eventually his desire overwhelmed him. “Please,” he begged, eyes still closed. 

“Please?” Sean teased. “Please what, Nicholas? You're going to have to be very clear when you ask for something. I wouldn't want to do something to you that you don't want.”

Nick took a deep breath to steady his racing heart. He was already mostly naked and bent over his captain’s desk. Was he really going to ask the man to spank him too? “Please,” he said. Apparently he was going to ask. “Please spank me, Sir.” 

Sean moaned low in his throat. “Of course, Nicholas. How could I say no when you asked me so nicely?” He ran his hands over Nick’s ass. “You’ll tell me if it's too much?”

“Yes,” Nick hissed. “Just do something.” His cock was fully hard and weeping and it hadn't even been touched yet.

Sean took a small step back to give himself more room before landing a smack on Nick’s other asscheek. When the man moaned in pleasure and pushed back against Sean’s hand he knew he was free to let go. He began raining hits down on Nick’s ass, making sure to spread them around evenly. He held back a bit, just aiming to bring a nice shade of red to Nick’s cheeks and ensure the detective would feel him the next day.

“That’s a lovely color,” Sean said when he’d finished. “Do you feel alright, Nicholas?” He rubbed his hands lightly over Nick’s ass to sooth the burn a little. 

“Other than being desperate to come?” Nick huffed. “Yeah, I’m fine.” The pain in his ass was flaring but, instead of being bothered by it like he would have expected, he found he loved the burn. The hits had put all of his senses on edge and made each of Sean’s touches feel even more electric against his skin.

“I wonder if you could come just from me spanking you,” Sean mused. “Maybe we’ll have to test that one day.” He leaned down and placed a line of kisses up Nick’s spine. As he continued kissing and tasting the beautiful expanse of skin below him, Sean wrapped an arm around Nick’s hip and gripped the younger man’s cock in his hand. “Right now though, I want you to come with my hand on your cock while you think about what it will be like to come in to work tomorrow.”

“Please,” Nick begged, hips jerking to get more pressure on his aching dick. 

Sean began moving his hand but kept his pace slow. “I think I'll call you and Hank in for a briefing tomorrow morning,” he said slyly. “See if you can be in here and not blush thinking about getting spanked over this desk.” He tightened his grip and started pumping Nick faster. “Maybe I'll make you both sit in those chairs while we talk. Hank will be fine obviously but you won’t be. You’ll be nice and sore both from the spanking I just gave you and from the thorough fucking I'm going to give you soon.” Sean swiped a thumb over the tip of Nick’s cock, spreading a bead of precum around to help ease his movements. “Will you be able to behave tomorrow, Nick? Or will you be squirming around in your chair making Hank ask questions you don’t want to answer?” the royal teased. 

“I’ll...I’ll be good,” Nick promised, impressed that he was still able to form coherent sentences though his lust fuelled haze.

“Good boy,” Sean praised. “Now come.” He twisted his wrist just so and Nick erupted, his release shooting onto the floor. Sean lightly pumped the younger man through his orgasm before he stepped back and moved his hands to rub up and down the Grimm’s back. 

“You didn't come,” Nick mumbled once he was able to talk again. He pushed himself up from the desk and turned to look at Sean over his shoulder.

The older man chuckled. “Oh we’re not done yet, Nicholas. I did promise you a thorough fucking after all.”

“Now that you mention it I do recall an intriguing claim about you being able to make me feel you for a week,” Nick replied with a cheeky grin on his face.

“You should know I always keep my promises,” Sean said with a smirk. He kept eye contact with Nick while he picked up the bottle of lube and poured a generous amount onto his fingers. Once he’d spread the gel around, Sean put his left hand between Nick’s shoulder blades and pushed the detective back down against the desk while his right hand slid between the younger man’s red asscheeks to tease his hole.

Nick was glad there wasn't anyone else working because it meant no one was around to hear the moan he let out. “Please, Sean,” he begged. “Please get in me. I need it.” It was the truth. His cock was starting to grow hard again and he knew he wouldn't be truly satisfied until he was worn out and well used.

“Such nice manners,” Sean teased. As a reward he slowly slid one long finger into Nick’s ass, pushing until the digit was fully buried inside. 

“So good,” Nick mumbled, hands clenching on the beside his head. 

Sean smiled. “It will be even better soon,” he promised. He twisted his finger and moved it in and out, getting Nick’s hole ready for more. He wanted the Grimm to be sore in the morning but he refused to cause the man under him any real pain. When the muscle had loosened Sean added a second finger and continued to work Nick open. “You’re so tight,” he said, voice rough with his ever building desire. “I’m sure it will feel amazing to fuck you.” He pushed his fingers back in quickly, rubbing against Nick’s prostate.

“It’s been awhile,” the Grimm admitted, a little embarrassed. He was far from a virgin but it had been years since he’d last slept with a man. 

“Good,” Sean hummed. “I’ll quite enjoy fucking you open and impaling you on my cock.” In an effort to match his actions to his words the older man drove a third finger into Nick’s willing hole.

“Fuck,” Nick moaned. He’d always had a slight kink for dirty talk but Sean’s words were driving him insane. His cock was fully hard and aching again and beginning to drip a bit with precum.

“We’re all tested regularly so I know you're clean, but do you want me to use a condom?” Sean asked, his fingers continuing to pump in and out of Nick’s ass. “Cleanup is easier and I know not everyone likes the feeling of having cum inside them.” It was hard for him to act calm and keep his voice level while saying that but he managed it. While he would respect whatever Nick asked, he didn't want to wear a condom. He wanted to mark Nick in the most primal way and fill the younger man up with his cum. If it was up to him he would keep his seed inside Nick as long as possible.

Nick pushed up on the desk a little so he could look at Sean over his shoulder. “Are you kidding? I don't want you in a condom, Sean,” Nick said with fire in his eyes. “I want to feel every inch of your delicious cock in my greedy hole and I want to be filled up with every last drop of your cum. Mark me, Sean. Make me yours.”

Sean growled--actually growled--at that and surged forward to claim Nick’s mouth. “I'm going to ruin you,” he promised when they broke apart for air. He spread his fingers once more and twisted his wrist as he pulled his fingers out to lube up his rock hard cock. Nick whined at the loss of his captain's fingers but Sean hushed him. “Don’t worry, my sweet Grimm,” he said, lining up his cock. “You won’t be empty for long.” True to his word, Sean immediately slammed inside Nick’s tight ass.

Nick let out a shout at the sudden intrusion. He’d forgotten how much he loved the feeling of being so completely filled. Sean’s cock was magnificent--stretching Nick and leaving a pleasurable burn as it touched every sensitive spot inside him. 

“So big,” Nick moaned. Even with the careful prep Sean was still a large man and Nick knew he truly would be feeling the encounter for days afterwards.

Sean chuckled. “You did say you hoped I was proportional everywhere.” He adjusted his grip on Nick’s hips so that he could drive into the Grimm deeper. “How does it feel? Tell me.”

“P...perfect,” Nick stuttered out, struggling to talk while Sean was fucking his brains out. “Feel so full.” His words turned to meaningless moans when Sean shifted a tiny bit to be hitting Nick’s prostate on every thrust.

“You feel perfect too,” Sean said in response. “So hot and tight as you clench around me. Your ass is pulling me in and begging for more,” he teased. He continued moving his hips, getting both men closer to their release. 

After so much buildup Sean knew he wasn't going to last as long as he would have liked. Truthfully he would happily continue fucking Nick for hours if the man let him. He wanted to leave a good impression though so he worked to give Nick as much pleasure as he could, hoping the detective would be willing to stay with him so that they could do this again in the future.

“Sean I need to come,” Nick begged. “Please.” He did his best to push back against Sean’s thrusts, taking the man's thick cock as far into him as he could. 

“You can come, Nick,” Sean soothed. “Whenever you're ready.” He took one hand off of Nick’s hips so that he could wrap it around his cock.

After two pumps Nick was coming for the second time that night. As he came his ass clamped down and the added pressure triggered Sean’s release. Nick moaned as he felt the streams of hot seed shoot inside his well-used ass.

“So good,” Nick said, reduced to simple sentences due to the blissful haze in his brain.

Sean leaned over Nick to kiss and rub at the Grimm’s back and shoulders. “You were amazing,” he praised softly. “Such a good boy.”

They remained in their positions for a few minutes until Sean’s cock was totally soft and Nick’s legs were ready to collapse. Disappointed, but not having any other choice, Sean slowly pulled out of Nick. He watched for a moment as a line of his cum trickled out of the detective’s stretched hole before collecting it with his fingers and shoving it back inside Nick’s ass. The man groaned at the feeling of the probing fingers inside his oversensitive channel but pushed back on them all the same.

“Next time I'll use a plug,” Sean promised. “Keep you filled with my seed for hours.”

“Fuuuuuck,” Nick moaned, clearly turned on by the idea.

Sean smirked as he pumped his fingers lazily. “With the plug in you’d also be kept open nice and wide for me,” he continued. “After a short break I could just easily slip back inside and fill you up with a second load. Maybe even a third. Would you like that?”

Unable to form words, Nick simply nodded quickly. His eyes were closed as he imagined what that would feel like. 

Sean chuckled as he took in his Grimm’s blissed-out look. “I see you like that idea. I think I have a number of toys that you would like,” he said, teasing. “For now though, let’s just rest.” Sean removed his fingers from Nick’s ass. He helped Nick pull his boxers and jeans back up and got his own pants back in place--they could worry about shirts later--then he sat down in his plush office chair and slowly pulled Nick into his lap. Sean whispered soothing praises in Nick’s ear and ran a hand through his hair. Although he was often a fan of fast and rough sex like they'd just had, Sean also took great pleasure in holding and comforting his partners. Hopefully he wouldn't be having any other partners anytime soon though. He wanted to be with Nick for a long time--maybe even forever, but it was too soon to say those types of things.

“You know,” Nick said as they basked in the afterglow. “I have my own list of fantasies.”

“Oh? Any you'd like to share?” Sean asked with a smirk, ignoring the sense of pride he felt to know Nick wanted to be with him again. He had a feeling that he would greatly enjoy anything Nick had in mind.

“Mmm.” Nick took a moment to run his eyes down his captain’s form. “What would you think about doing this in your uniform next time?”

Sean moaned. Yes, this would be a long and very pleasurable relationship indeed.

 

 

 

 

**Author's Note:**

> I hope you enjoyed the story! This has been in the works for a while so I'm excited to finally share it. Comments/kudos are always appreciated. :)


End file.
